I have a 93 Z28 with the non-vented cap, I was wondering if the vented cap can be used and be a direct bolt-on. And whats the best brand to put back on, i was thinking about the MSD cap and rotor. Thanks, Daniel

 

The vented style distributor uses a vented "base" as well as a vented cap. So without changing the back, you can't simply change the cap.

The OEM distributors were not interchangable from vented to non-vented unless you changed the camshaft and timing covers. However MSD's early model drop in as well as the later style are BOTH vented. The early model even comes with the hoses etc to install it.

So if you want a vented system without changing the cam and timing cover, the only way I know to do it is with the new MSD.

Here's the instructions for installation.
http://www.msdignition.com/pdf/8381_frm27275.pdf

 

Long ago there was an article on how to vent the non-vented opti. They used a vented cap and installed a vent in the opti housing. Knowing that, I don't see why a vented cap could be installed (though you would get no benefit unless you did the conversion to the housing).

 

Here's the 'Corvette Fever' article:
http://www.corvettefever.com/howto/16758/

 

you can run a vented cap on a non-vented opti, but you need to run the non-vented seperator(white plastic)

I am doing this now

am i going to modify my opti to run vented by adding a vent fitting into the base, and installing the hoses